Dow Jones Newswires reports that Leap Wireless, which has lagged its peers over the past year, posted a wider fourth-quarter loss but started to show signs of a turnaround. The US operator reported a loss of US$249.4 million, compared with a year-earlier loss of US$61.9 million. Revenue jumped 13 percent to US$708 million. The prepaid wireless provider returned to customer growth in the fourth quarter. More importantly, 40 percent of its mobile phone customers opted for a smartphone, which yield higher monthly rates and result in fewer defections down the line.